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The Truth About Feminized Cannabis Seeds

Feminized cannabis seeds also known as fem seeds or female seeds have become increasingly popular this past decade. And yet, many ganja growers still have concerns. Some say that these seeds will produce more hermaphrodites while others claim that the process is unnatural or unethical.
In any case, it it a highly controversial subject. Some growers swear by fem seeds while others will only pop regular seeds.
We will first discuss the different methods used by breeders to produce fem seeds. Then, we will go over the myths and urban legends surrounding these controversial beans before weighing the pros and cons of regular vs feminized cannabis seeds.

How Breeders Make Feminized Cannabis Seeds

1 Rodelization

This is the old school method. Some breeders used to create feminized seeds using pollen from hermaphrodites. They would stress their plants on purpose by overfeeding, disturbing the light cycle, keeping the plants alive past their desirable harvest date…
Once these plants produced a few male flowers, they would harvest the pollen and use it for making seeds. Because the plants they were using weren’t sexually stable, their offspring also was prone to turning hermaphrodite.
This is the technique that gave feminized seeds their bad rep. Although most professional breeders no longer use that method, many growers still believe that fem seeds are more prone to hermaphrodism than regular seeds.

Rodelization process

The first feminized seeds were produced using hermaphrodites. This is what gave feminized seeds their bad reputation. Photo by Iznogood Khalifa.

2 Inhibiting The Ethylene Production

Female cannabis plants naturally produce Ethylene. Ethylene is a plant hormone that stimulates or regulates the opening of flowers and the ripening of fruit.
Applications that can inhibit the ethylene production will cause female plants to produce males flowers. These male flowers however will only produce “female pollen” as they only carry X chromosomes. Many products can inhibit the Ethylene production in plants. The main ones being silver thiosulphate, silver nitrate, colloidal silver and gibberellic acid. Contrary to popular belief, some of these products such as gibberellic acid (a natural hormone found in plants and fungi) or Colloidal Silver (suspension of silver particles in liquid) are non-toxic.
When resorting to this method, if the breeder uses 2 sexually stable females to make seeds, the offspring will also be sexually stable.

The Myths Surrounding Fem Seeds

Some myths and urban legends have been around ever since the first fem seeds appeared on the market. Let’s go over the main ones.

1 Growers are more likely to end up with hermaphrodites when growing fems

This is by far the biggest myth. As mentioned above, It stems from the Rodelization method (creating feminized seeds using pollen from hermaphrodites). Nowadays most cannabis breeders resort to either colloidal silver (CS) or silver thiosulfate (STS) in order to “reverse” their female plants. As with regular seeds, if the parents the breeders use are sexually stable, their offspring will also be sexually stable. However the plants coming from female seeds are, on average, even more sexually stable than most regular strains. The reason for that greater stability is because it is easier to stress test a female than it is to stress test a male.

Reversed Cannabis Plant

Pure Cambodian Female that has been reversed for making quality feminized seeds.

2 Feminized seeds are not natural because in the wild, there are only regular cannabis seeds

Since hermaphroditism is an undesirable trait, modern breeders have made modern cannabis strains more sexually stable than most landraces and wild varieties. Hermaphroditism is a natural survival mechanism. In their natural environment, plants often turn hermaphrodite as a last ditch attempt to reproduce when there is no male around. Therefore some wild strains and local cultivars also produce feminized seeds.

3 Fem beans produce toxic flowers that are dangerous to smoke

Only the female plants that breeders spray to produce female pollen can be toxic. The plants grown from feminized seeds however are perfectly safe to smoke or eat.

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The Pros And Cons of Feminized Seeds

After presenting the different methods breeders use to make feminized seeds and busting some of the myths concerning these controversial beans, let’s now weigh the pros and cons of Fem VS Reg seeds.


It Saves Time, Space And Money

Growers don’t know the sex of their plants until the second week after the 12-12 flip. Therefore, those growing regular seeds have to throw away about 50% of their plants (The male plants) after dedicating time and resources for several weeks.

Fems Are Beginner Friendly

Growers have to be careful with male plants since they could seed their whole crop. With feminized seeds, all the plants will be female so beginners don’t have to worry about spotting and culling out the males before they start dropping pollen.

It Allows Growers To Grow Fewer Plants

Because female seeds only give female plants (Over 99% of the time), growers wanting to keep a low plant count can only sprout a few seeds. With fems, no need to grow twice the amount of plants and then cull out all the males.

Female Seeds Give Both More Sexually And Genetically Stable Plants Than Regular Seeds

It is tricky to know which traits a male plant will pass on to its female offspring. Unlike with female plants you cannot directly observe the female attributes that males carry in their genes. Likewise, it is also harder to stress test male plants in order to cull out the hermaphrodites. For these reasons, on average, fems are more uniform and less prone to herming. Of course it also greatly depends on how serious the breeder is and some feminized seeds may give bad results.


It Makes Pollination Difficult

The Plants Have to go through the reversal process before then can produce pollen. This takes time, skills, and some of the products required can be hard to get. Furthermore, not all female plants can be successfully reversed! Some will produce sterile pollen or even empty pollen sacks.

Feminized Cannabis Seeds Cost More Upfront

Reversing female plants requires resources, skills and doesn’t yield as much pollen as with male plants. Thus, female seeds cost more than regular seeds.

It Forces Small Hobby Growers To Buy New Seeds Year After Year.

Producing feminized pollen takes time, trial and error as well as money. For these reasons, most hobby growers prefer buying new seeds rather than making their own. Especially when these growers opt for autoflowering strains. They cannot clone these plants and have to buy new seeds often.

Rare Strains Could Disappear Faster

Feminizing rare heirlooms or landraces would cause them to disappear faster since many plants are needed for preserving a cannabis strain. In that case, most local farmers would not have the knowledge or the means to keep these cultivars alive.


Because they answer different needs, both feminized and regular seeds have their place in the cannabis world. Even if fem seeds offer many advantages, it is also paramount to preserve strains in their regular form for preservation’s sake.